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Formation and evolution of S0 galaxies: a SAURON case study of NGC 7332

2004; Oxford University Press; Volume: 350; Issue: 1 Linguagem: Inglês

10.1111/j.1365-2966.2004.07704.x

1365-2966

J. Falcón‐Barroso, R. F. Peletier, Éric Emsellem, H. Kuntschner, Kambiz Fathi, Martin Bureau, Roland Bacon, Michele Cappellari, Y. Copin, Roger L. Davies, P. T. de Zeeuw,

Stellar, planetary, and galactic studies

We present SAURON integral-field observations of the S0 galaxy NGC7332. Existing broad-band ground-based and HST photometry reveals a double disk structure and a boxy bulge interpreted as a bar viewed close to edge-on. The SAURON two-dimensional stellar kinematic maps confirm the existence of the bar and inner disk but also uncover the presence of a cold counter-rotating stellar component within the central 250 pc. The Hbeta and [OIII] emission line maps show that the ionised gas has a complex morphology and kinematics, including both a component counter-rotating with respect to the stars and a fainter co-rotating one. Analysis of the absorption line-strength maps show that NGC7332 is young everywhere. The presence of a large-scale bar can explain most of those properties, but the fact that we see a significant amount of unsettled gas, together with a few peculiar features in the maps, suggest that NGC7332 is still evolving. Interactions as well as bar-driven processes must thus have played an important role in the formation and evolution of NGC7332, and presumably of S0 galaxies in general.